Help, opinions needed. * Warning long rambling post :) * - G

[steveperry]

I had the main a/c control unit replaced (the dials, module etc that sit behind the dash) because of a faulty light on the bottom "REST" button. I tested the car thoroughly after the garage fitted the replacement unit and all worked fine, dials did what they were meant to and buttons functioned correctly.

However, the next day when I started the car for the first time in the day the a/c fan went on full blast, even the 2 auxilary fans were going, and none of the buttons or fan speed dial had any effect. After running the car for approx 5 mins and frantic button mashing I then switched the car off then on re-starting the car the a/c behaved normally as if nothing has happened.

So now 50% of the time when I first start the car in the morning everything is fine and the other 50% of the time the a/c is uncontrollable running at full kahonas. But the weird thing is after the first journey the car a/c behaves normally for the rest of the day.

I'd rather not go back to the garage that did the work as they are 200 odd miles away and I can't afford to keep trapsing back to them. Plus they don't seem the most competent people in the world, I bought the car from them and they did me a good deal to be fair but I don't trust them for mechanical work. The last time I took the car to them for the a/c to be looked at they dented the car grr they put it all right eventually but it was a pain in the arse to sort. I did buy the car with a 12 month warranty.

Sorry this is a long rambly email, I guess my question is "have they replaced one faulty unit with another faulty one, or, could it be explained by a loose fitting plug that fits into the socket located on the back of the module?"

Any ideas guys? hehe here's one for you Andy.

Grr all for a poxy tiny red light not working on recirculating air... if I knew it would cause all this hassle, I'd have left it well alone.

Thanks guys, all help/opinions mucho appreciated.

*edit* This all happened over the Easter w/e so they've also been closed for 4 days.

S.

(Edited by steveperry at 7:32 pm on April 2, 2002)

 

[Andy]

Help, opinions needed. * Warning long rambling post *

Hi Steve,

It does sound like a faulty unit. Its as if there is a short putting  a feed to the high to the fans. The only way to check would be to get a test unit and fit and try for a couple of days.

By the way what vehicle is it?

Regards
Andy @ www.mercedesservicing.com

 

[steveperry]

Help, opinions needed. * Warning long rambling post *

Thanks very much Andy, as ever your input is greatly appreciated. Do you reckon the unit is covered by a car warranty?

The vehicle is a '98 C240 Sport. That means it has the cream coloured dials with black numerals as opposed to the more common black surround dials with white numerals.

Can these "modules" be worked on at all? It seems ****** crazy that all that was wrong on the original control unit was one small LED light was bust on the "REST" button so that it didn't light when on internal air recirc and the garage replaced the whole unit. They claimed the thing cost close to £300-00 but did the replacement at no cost to me. I wonder whether they would have got some kind of "trade in" for my old faulty a/c control unit.

Does it seem like coincidence that the problem seems to manifest itself when the car is first switched on during the day and then on subsequent journeys during the day the problem disappears?

One other thing Andy, when they first fixed the car and I arrived to collect it, I tested out the system and got exactly this problem, I asked them to fit the old unit back again, as the replacement seemed totally non-functioning, which they did. They were perplexed because they tested said unit the day before and told me all was well.

Anyways, I got a phone call 2 days later to say they had received a second replacement unit, which they fitted for me, I test it at the garage and all is well, yet next day the very same gremlins are back. If I take the garage at their word, two replacement units are causing the same intermittent effect which seems a little hard to believe, i.e. the problem may lie somewhere else in the car. Either that or the garage have just given me back the first replacement unit and hoped the problem would go away.
Thanks again for your time & input Andy.

S.

 

[steveperry]

Help, opinions needed. * Warning long rambling post *

D'Oh... double post

S.


(Edited by steveperry at 1:47 am on April 3, 2002)